<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style type="text/css">
	#main{
		width: 600px;
		border: 5px solid blue;
		overflow: hidden;
	}
	#main div{
		width: 180px;
		height: 80px;
		margin: 10px;
		background: purple;
		float: left;
	}
	#hd{
		width: 500px;
		height: 500px;
		background: green;
	}
</style>
</head>

<body>
<!-- 如果一个父级元素中的子元素都有浮动属性，那么这个父级元素就无法被它的子元素撑开高度 -->
<div id="main">
	<div></div>
	<div></div>
	<div></div>
	<div></div>
	<div></div>
	<div></div>
	<div></div>
	<div></div>
	<div></div>
	<div></div>
</div>
<div id="hd"></div>
</body>
</html>
